In this paper, flocculation process was applied to the treatment of potato starch wastewater. The Influence of flocculent types, dosage of flocculants, pH, dosage of coagulant aid polyacrylamide (PAM) and sedimentation time on flocculation efficiency was studied, and principal factors of influence flocculation pretreatment of potato starch wastewater and the optimum flocculation conditions were determined by orthogonal experiment. On the optimum conditions which had the advantage of better treatment efficiency with chemical oxygen demand (COD) removal rate of 40.55% , the suitable pH(7) in favour of the following biological treatment, high yield of sludge of 1.59g/L wastewater which could be used as animal feed or fertilizer and increase economic benefits.